1. Field of the Invention
This invention relates to mobile argricultural balers.
In the mechanization of the farm there has been a great deal of emphasis on the mechanical harvesting and gathering of crops. One of the machines which has been developed is the mobile baler which often is of the tractor pull type but also may be of the self-propelled type. Mobile balers move across fields to pick up crop laying in windrows or swaths and compress that crop into rectangular bales. The bale is of a convenient size and form for handling either manually or by machinery.
2. Description of the Prior Art
A conventional hay baler has a fore-and-aft extending bale case and a plunger reciprocable therein, both the bale case and the plunger being generally rectangular in transverse cross-section. The bale case has an inboard side wall provided with an inlet feed opening for crop material. The baler also has a crop pick-up and feed mechanism operable to deliver crop material through the inlet feed opening and into the bale case.
The reciprocating plunger operates to compress the crop material within the bale case to form bales. When the plunger is retracted, the bale case inlet feed opening is open and the operation of the feed mechanism is timed relative to the plunger to deliver a charge of crop material through the inlet feed opening and into the bale case at that moment. When the plunger moves in its working direction to compress the delivered charge of crop material, one side face of the plunger closes the inlet feed opening. However, the timing of the feed mechanism is such as to ensure withdrawal of the feed mechanism from the feed opening before the latter is closed by the plunger. In order to separate the crop material within the feed area outside the bale case from the material just delivered into the bale case by the feed mechanism, the plunger is provided with a knife which cooperates with a stationary knife or shear bar positioned along the bale case inlet opening to sever the crop material during the working stroke of the plunger.
Each completed bale is banded with twine or wire. The tying medium is threaded around each bale by needles which deposit with precision the tying medium in knotter or twister mechanisms which operate to knot or twist the ends of the twine or wire, respectively. The tied bales are then ejected from the baler.
The terms "forward", "rearward", "left", "right", etc. when used throughout this specification in connection with the baler and/or components thereof are determined by facing in the direction of operative travel of the baler in the field.
In most baler designs known today, the baler mechanism is mounted on top of a tranverse wheel axle and supported on a pair of ground wheels at opposite ends of that axle. The axle extends transversely below the feed mechanism and rearwardly of the crop pick-up means. A baler of the foregoing type comprises a relatively large number of components, whereby the weight of the machine is comparatively high, the cost is accordingly high and the design is complicated. Nevertheless, the structural strength has not always been sufficient.
Because of the weight of the baler and because of the flotation characteristics required, wheel hubs and tires of a certain size have commonly been used. Also, it is desirable, for a number of reasons, to have the baler mechanism at a predetermined, relatively small, height above the ground. A low profile machine is always desirable, not only to minimize the size and weight of the components but also to allow the operator to see from his seat the discharge end of the bale case so that he can check whether the bales are being properly completed. Also, as the crop material is picked up from the ground and supplied to the feed mechanism which is at the level of the infeed opening in the bale case, the underside of the feed housing and the bale case should be at the same level as the discharge end of the pick-up means. Conventional pick-up means operate satisfactorily provided their lift does not exceed a certain limit. Hence the bale case and feed housing also should not be positioned higher than a predetermined, relatively small, height above the ground.
In view of the wheel hub and tire sizes dictated inter alia by the machine weight, and in view of the optimum height of the baler mechanism above the ground, it has been common practice to provide one wheel to the left of the bale case. This wheel extends as high as or, as is more often the case, above the level of the underside of the bale case. The right-hand wheel conventionally is positioned rearwardly of the right-hand end of the pick-up means and to the right of the extreme right-hand end of the feed mechanism.
During recent years, however, the size of the baler, especially the width of the pick-up means, have continuously been increased to provide higher capacity balers. With the advent of giant combine harvesters and haytools of ever-increasing size, on the one hand, and with the demands for ease of operation, on the other hand, it is becoming necessary to have still wider crop pick-up means.
However, the maximum road transport width for pull-type agricultural machines tends to be restricted to 2.5 meters in several countries. Also, the practical maximum width for transporting balers on trucks is 2.5 meters. This width is already attained or even exceeded by most of the present day high-capacity balers. Thus the limiting factors for the width of the pick-up means are on the one hand, the legal and practical transport requirements dictating a maximum overall width and, on the other hand, the size and position of the wheels and the width of the bale case, the latter being determined by the width of the bales to be made.
The wheels of conventional balers are mounted on spindles fixed to the main transverse axle. This is disadvantageous especially when the baler is pulled at high speed over rough terrain because the resulting vibration of the machine can loosen components and the machine can be subjected to high peak loads. Occasionally, the proper operation of the baler also may be hindered by this vibration.
Conventional balers usually comprise a welded main body formed by a generally fore-and-aft extending bale case and the transverse feeder housing secured to the bale case intermediate its ends. The tranverse wheel axle already mentioned above is also a relatively large welded assembly. Welding normally imparts sufficient strength to a structure but it is a relatively expensive and slow operation and can cause problems of deformation of the workpiece, especially when large assemblies involving much welding are involved. Furthermore welding can create substantial air pollution in a welding shop. The foregoing illustrates limitations of the known prior art. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations as set forth above.